Hi,
This is v5, part 3 of three series for PCI endpoint DMA.
The three series are:
* part 1: dmaengine: dw-edma: Prepare for PCI EP DMA
* part 2: PCI: endpoint: Expose endpoint DMA resources
* part 3: PCI: endpoint: Add PCI DMA endpoint function
This series adds the host-side metadata parser, the pci-epf-dma
endpoint function driver, and documentation.
The endpoint function exposes selected endpoint-integrated DMA channels
as a separate PCI DMA controller function. The host-side dw-edma-pcie
driver discovers the BAR metadata and registers the exposed channels
with DMAengine. The endpoint function keeps the metadata BAR stable and
uses a separate DMA window BAR for resources that need dynamic subrange
mappings.
No fixed PCI ID is assigned. Users provide the PCI vendor/device ID
through configfs and bind dw-edma-pcie explicitly, for example with
driver_override.
This series depends on parts 1 and 2:
[PATCH v5 00/14] dmaengine: dw-edma: Prepare for PCI EP DMA (part 1/3)
https://lore.kernel.org/r/20260717050308.2144108-4-den@valinux.co.jp/
[PATCH v5 0/6] PCI: endpoint: Expose endpoint DMA resources (part 2/3)
https://lore.kernel.org/r/20260717050635.2145014-1-den@valinux.co.jp/
One open question is how to support endpoint controllers with only one
PF. Keeping DMA in a separate EPF requires multi-function endpoint
support. Folding it into vNTB would work on single-function
controllers, but would also couple the two implementations. This series
keeps the separate EPF model.
The v5 RC-to-EP path was retested with a small out-of-tree DMAengine
client on RK3588 and SpacemiT K3 endpoint setups.
Best regards,
Koichiro
---
Changes in v5:
- Quiesce each shared-register direction once during channel release.
Changes in v4:
- Rebased onto the new parts 1/2 series.
- Support IOMMU-backed EPCs by DMA-mapping the dynamic DMA-control
MMIO BAR submaps for the EPC parent, keeping descriptor DMA
addresses unchanged.
Changes in v3:
- Select endpoint DMA match data before copying DMA data and require
driver_override for the generic endpoint DMA fallback. (Sashiko)
- Accept HDMA native linked-list endpoint DMA metadata.
- Consume logical DMA channels separately from descriptor memory
resources.
(Sashiko)
- Delegate channels through the EPC DMA channel delegation API instead of
v2's EPC-provided DMAengine filter callbacks.
- Allow HDMA native linked-list channels to be delegated at channel
granularity.
- Preserve HOST_REQ across link-down and retry DMA window submaps on the
next link-up.
- Drop trailing colons from documentation subsection headings. (Randy)
- Document HDMA native linked-list mode support and the current non-LL
limitation.
Changes in v2:
- Follow the part 1/3 and part 2/3 v2 channel-claim model: pci-epf-dma
now claims delegated channels through DMAengine filter information from
EPC auxiliary resources.
- Select raw-address dw-edma-pcie platform ops from the endpoint DMA
match entry instead of using a match flag.
v4: https://lore.kernel.org/r/20260710082727.2397253-1-den@valinux.co.jp/
v3: https://lore.kernel.org/r/20260620170844.3757241-1-den@valinux.co.jp/
v2: https://lore.kernel.org/r/20260525063456.3317509-1-den@valinux.co.jp/
v1: https://lore.kernel.org/r/20260521063638.2843021-1-den@valinux.co.jp/
Koichiro Den (3):
dmaengine: dw-edma-pcie: Discover endpoint DMA metadata
PCI: endpoint: Add DMA endpoint function
Documentation: PCI: Add PCI DMA endpoint function documentation
Documentation/PCI/endpoint/index.rst | 2 +
.../PCI/endpoint/pci-dma-function.rst | 188 ++
Documentation/PCI/endpoint/pci-dma-howto.rst | 201 +++
drivers/dma/dw-edma/dw-edma-pcie.c | 401 ++++-
drivers/pci/endpoint/functions/Kconfig | 13 +
drivers/pci/endpoint/functions/Makefile | 1 +
drivers/pci/endpoint/functions/pci-epf-dma.c | 1524 +++++++++++++++++
7 files changed, 2328 insertions(+), 2 deletions(-)
create mode 100644 Documentation/PCI/endpoint/pci-dma-function.rst
create mode 100644 Documentation/PCI/endpoint/pci-dma-howto.rst
create mode 100644 drivers/pci/endpoint/functions/pci-epf-dma.c
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2.51.0